Ah yes.........A lock ring tool for an Ashatabula (one piece all steel crank) bottom bracket commonly seen on lower prices bikes. Very old still in use today. It should also fit a more modern 3 piece, ball and cup adjustable BB. Park makes a tool similar to that one; Park Tool Co. » HCW-5 : Crank and Bottom Bracket Wrench : Crank Tools Very cool tool where did you get it?

Ah yes.........A lock ring tool for an Ashatabula (one piece all steel crank) bottom bracket commonly seen on lower prices bikes. Very old still in use today. It should also fit a more modern 3 piece, ball and cup adjustable BB. Park makes a tool similar to that one; Park Tool Co. » HCW-5 : Crank and Bottom Bracket Wrench : Crank Tools Very cool tool where did you get it?